Merge pull request #148 from mlibrary/fastapi-metrics

Fastapi prometheus metrics

Author: niquerio

api/catalog_api/main.py

@@ -1,4 +1,7 @@
 from fastapi import FastAPI, HTTPException
+from prometheus_fastapi_instrumentator import Instrumentator
+from prometheus_client import Histogram
+
 from catalog_api import schemas
 from catalog_api.solr_client import NotFoundError
 from catalog_api.record import record_for
@@ -7,6 +10,13 @@
     title="Catalog Search API", description="REST API for Catalog Search Solr"
 )
 
+Instrumentator().instrument(app).expose(app)
+
+RECORD_HISTOGRAM = Histogram(
+    "catalog_api_record_request_duration_seconds",
+    "Length of api request for a catalog record",
+)
+
 
 @app.get(
     "/records/{id}",
@@ -18,6 +28,7 @@
     },
     response_model_exclude_none=True,
 )
+@RECORD_HISTOGRAM.time()
 def get_record(id: str) -> schemas.Record:
     """
     Gets a record from catalog solr. The record is fetched by the solr id, which

api/catalog_api/solr_client.py

@@ -1,19 +1,25 @@
 import requests
 from requests.auth import HTTPBasicAuth
 from catalog_api.services import S
+from prometheus_client import Histogram
 
 
 class NotFoundError(Exception):
     pass
 
 
 class SolrClient:
+    SOLR_HISTOGRAM = Histogram(
+        "catalog_api_solr_record_request_duration_seconds", "Length of solr requests"
+    )
+
     def __init__(self) -> None:
         self.session = requests.Session()
         self.base_url = f"{S.solr_url}/solr/biblio"
         if S.solr_cloud_on:
             self.session.auth = HTTPBasicAuth(S.solr_user, S.solr_password)
 
+    @SOLR_HISTOGRAM.time()
     def get_record(self, id: str):
         params = {"q": f"id:{id}"}
         url = f"{self.base_url}/select"

api/poetry.lock

@@ -18,6 +18,7 @@ fastapi = "^0.115.11"
 uvicorn = "^0.34.0"
 httpx = "^0.28.1"
 pymarc = "^5.2.3"
+prometheus-fastapi-instrumentator = "^7.1.0"
 
 
 [tool.poetry.group.dev.dependencies]